1. Field of the Invention
The present invention relates generally to apparatus for fluid-treating photographic film having a disc-shaped configuration. More particularly, the invention relates to fluid-treating apparatus in which a plurality of film discs supported on a spindle are transported from one bath of processing solution to another for immersion in the respective baths.
2. Description of the Prior Art
A variety of devices are known for processing photographic film. Common concerns for processing film in these devices are the desire to minimize or eliminate mechanical contact with the front and back surfaces of the film and the desire to obtain an intimate contact between the film surfaces to be treated and the processing solution, without any external contaminates or any chemical carryover between different processing solutions. Further desires from the economic viewpoint are to provide processing apparatus which is low in cost, yet efficient in operation, and to minimize the quantities of solution used.
The majority of known processing apparatus has been devised for use with strip film. Although processing apparatus for strip film has been used successfully for many years, it is common in such processing apparatus for the front and back surfaces of the film to have mechanical contact with an array of drive rollers and guide rollers for transporting the film between successive baths of processing solution. As is well known, this mechanical contact can lead to problems which may affect transport time and image quality, for example.
Devices for processing discrete units of film are not as common as those for processing strip film. One possible approach is to support a plurality of film chips on a rack or in a tray and successively dip the rack or tray in different baths of processing solution. For example, U.S. Pat. No. 3,641,906, issued Feb. 15, 1972, discloses processing apparatus in which a tray of film chips suspended from a carrier rod is transported successively between baths of processing solution by respective pairs of transfer arms engagable with the carrier rod. Each pair of transfer arms is rotated 360.degree. outside the baths, first in the initial 180.degree. to transfer the tray of film chips from one bath to the next bath, and then in the final 180.degree. to release the tray and return to alongside the former bath. The pairs of transfer arms are pivotally mounted between the successive baths of processing solution, which requires that the successive baths be spaced apart a sufficient distance to allow for the 360.degree. rotation of each pair of transfer arms. This spacing apart of the successive baths, as well as the external rotation of the transfer members, adds to the overall dimensions of the processor, which increases its space requirements and possibly its cost.
More recently, discrete units of film having a disc-shaped configuration have been developed for use in a modern camera. The film disc and the camera are disclosed in commonly assigned U.S. Pat. No. 4,194,822, issued Mar. 25, 1980. The film disc has a central aperture about which is concentrically disposed a plastic hub member. The hub member is permanently attached to the film disc and includes a keyway by which the hub member can be secured to a keyed spindle for rotation of the film disc during processing. An example of a processor for the film disc is disclosed in commonly assigned U.S. Pat. No. 4,112,452, issued Sept. 5, 1978. The disclosed processor includes a keyed spindle on which a plurality of film discs can be supported in substantially parallel hub-to-hub relation. The spindle and the film discs are rotated in successive baths of processing solution and are transferred from bath to bath by respective pairs of forked lifter arms which raise a rack carrying the spindle and the film discs from one bath and lower the rack into the next bath. The pairs of lifter arms are moved outside the baths by an endless drive chain along individual rectangular paths which partially coincide alongside each bath to transfer the rack from one pair of lifter arms to the next pair.
Other examples of processors for film discs are disclosed in commonly assigned U.S. Pat. Nos. 4,112,453 and 4,112,454, both issued Sept. 5, 1978 and commonly assigned U.S. Pat. Nos. 4,178,096, issued Dec. 11, 1979 and 4,167,320, issued Sept. 11, 1979.
In summary, much of the known art which relates to processing discrete units of film discloses transfer members for transporting the film units between successive baths. These transfer members, as evidenced by the above-described prior art, move along closed or continuous paths which are located outside the baths. Such location and configuration of the respective paths adds to the overall dimensions of the processor, increasing its cost and space requirements. Several examples of the above-described prior art use a rack or a tray to successively immerse the film in different baths of processing solution. While these examples have generally performed satisfactorily, dipping the rack or the tray in the different baths increases the chemical carryover between the various solutions (which affects the quality of development) and makes access to the film units in the respective baths difficult.